Electrodeposition of bismuth at a graphene modified carbon electrode and its application as an easily regenerated sensor for the electrochemical determination of the antimicrobial drug metronidazole

Metronidazole is a well-known antimicrobial drug that belongs to the nitroimidazole family of antibiotics. It has been widely used in the treatment of infections, but its accumulation in aquatic environments is an emerging concern. In this study a glassy carbon electrode was modified with graphene (Gr) nanoplatelets and bismuth. Both the Gr and Bi were electrochemically deposited onto the glassy carbon and the modified electrode was employed in the electrochemical detection of metronidazole. At the modified electrode, the reduction of metronidazole was found to be an adsorption-controlled reaction. The optimised sensor, which was fabricated within 6 min, exhibited good selectivity in the presence of various inorganic and organic compounds, good recovery in tap water, and exhibited a linear calibration curve extending from 0.005 to 260 μM, with a limit of detection of 0.9 nM. The sensor was easily regenerated through the simple oxidation of the Bi deposit followed by a 100 s reduction period in the Bi(III) solution to give a newly generated surface. Good reproducibility was achieved using this simple regeneration approach. [Display omitted] •A simple sensor fabricated using graphene and electrodeposited bismuth was formed and employed in the electrochemical detection of Metronidazole.•A wide dynamic linear region, extending from 0.005 to 260 μM with a LOD of 0.9 nM was achieved.•Very good selectivity was observed in the presence of various interfering ions.•The total time required to form the sensor was only 6 min.•The surface of the sensor was readily regenerated by renewing the Bi layer.